The project outlines research involving subhuman primates which includes a breeding program to provide animals of known health, age, and species for a group of satellite research programs investigating the nutrition-related disorders of the heart, lung, and circulatory systems. The Core Facility is currently responsible for the breeding program and purchase, conditioning, health surveillance, and intensive care of infant and adult animals of two species of New World and one species of Old World monkeys. The second major Core objective is to investigate certain nutritional requirements directly related to normal growth and development of the infant monkeys studied. The animals are maintained for investigative satellite units with research interests in atherosclerosis, lipid metabolism in tissue culture, development and use of blood substitutes, and protein-calorie malnutrition and mental development. Over 450 squirrel, cebus, and rhesus monkeys are cared for in the facility which produces approximately 75-100 infant monkeys per year for research by satellite units. Infants are nursery reared on semi-purified diets of our own design in accord with the requirements of satellite unit protocols. This also provides the opportunity for the Core to further explore nutritional problems such as those related to dietary fats, protein requirements for growth, optimum level of dietary fiber and minerals needed for normal development. The significance of these studies lies in the production of infant primates for longitudinal study of cardiovascular disease while maintaining control over a key variable, diet. These studies also offer extensive information in the increasingly important area of infant primate husbandry and are unique in their contribution to knowlege of primate nutrition, crucial to all future investigators using non-human primates for research. This program also supports a breeding program for New World monkeys that we have developed in Guatemala. BIBLIOGRAPHIC REFERENCES: Cirrhosis of choline deficiency in rhesus monkey. Possible role of dietary cholesterol. A.J. Patek, S. Bowry and K.C. Hayes; Proc. Soc. Exp. Med. 148: 370-374, 1975. Comparative Ultrastructure of Primate Fatty Streaks. K.C. Hayes and N.P. Westmoreland. In: International Workshop on Atherosclerosis, London, Ontario, Canada, 1976 (in press).